The aftermath of war

Tony Sale looks and sounds as if he has stepped out of a John Le Carré spy novel as he stands reminiscing in what was once the hub of Britain’s wartime intelligence.

The fate of nations, and the lives and deaths of countless people, rested on the codebreaking work that was done in these rooms at Bletchley Park, an hour’s train ride out of London.

Today, as it must have been back in 1944, there is the regular thrumming of a paper tape running with surprising speed over multiple rollers feeding data at 5,000 characters a second into a replica of the Colossus Mark 2 proto-computer.

This was used to break the Lorenz encryption used for Nazi high-command messages. By the end of the war 10 of these machines were at work and, if it had not been for Sale, a former MI5 boffin, they might have been largely lost to history. Even today you can find books on computer history that make no mention of them.

This is because the British Government forbade all mention of them, and of the Bletchley codebreaking, after the war. Eight of the machines were broken up and two went to the GCHQ signal intelligence centre at Cheltenham, where they remained in use until 1961. “It took that long for modern computers to catch up,” said Sale.

This secrecy had little effect on the development of computers: their time had come. Those Americans who mattered knew about Colossus, so it probably helped give early US computer projects official credibility and support. Max Newman, who first suggested mechanising Lorenz deciphering at Bletchley, led the team that built the Baby, the world’s first stored-program computer, at Manchester University.

Alan Coombs, who designed Colossus Mark 2, which was completed just in time for D-Day in 1944, went on to build the Post Office’s first computer, Mosaic. “He was an absolutely brilliant electronics engineer. Some of the things he did on the Mark 2 were exceptional,” said Sale. But the secrecy over Colossus hinde red the post-war work of Alan Turing and Tommy Flowers.

Flowers’ inability to cite the precedent of Colossus delayed until 1962 the opening of his great post-war project, an all-electronic phone exchange at Highgate Woods in London. Turing had a similar problem when he went to the National Physical Laboratory to build a machine called the Automatic Computing Engine (ACE).

It used just 850 valves, around a third of the number in Colossus 2 but an enormous number by the standards of the time, and Turing had a hard time trying to persuade his bosses of its feasibility. Finally he gave up fighting the bureaucrats and went to join Max Newman at Manchester. Flowers received an OBE and £1,000 after the war. Turing got not even the grace of a blind eye over his sexuality.

He killed himself in 1954, virtually unknown outside academia, after being convicted of gross indecency. The reasons for his suicide are unfathomable now but professional frustrations after the days of the war surely played a part.

Incidentally Derek Jacobi, the gay actor who played Turing in Hugh Whitemore’s play Breaking the Code, got a knighthood – doubtless deserved for a distinguished career, but a telling contrast nevertheless. And what was the point of all that cussed secrecy?

Sale says the Russians began using Lorenz enciphering machines captured from the Germans; this was at the start of the Cold War and Britain did not want it known that the cipher could be cracked. Actually Sale believes the British were even more devious. A former Bletchley worker, John Cairncross, was exposed in 1951 as a Russian spy who had passed on information during the war.

Sale reckons the British knew all along what he was doing, but allowed him to continue because Russians would not believe intelligence they were given officially by the British – including German plans for the pivotal Battle of Kursk.